Oxford scientists have set up a biotechnology company to develop the use of gene therapy in treating blindness, and the Wellcome Trust medical charity has invested 12 million pounds ($20 million) in the start-up.

NightstaRx plans to develop and sell therapies for retinal dystrophies - degenerative conditions affecting vision - by building on work carried out at the University of Oxford's Nuffield Laboratory of Ophthalmology, it said on Thursday.

Oxford-based researchers reported two weeks ago that an early-stage clinical trial using gene therapy had shown promise in a handful of patients with a progressive form of blindness called choroideremia.

The company has an exclusive licence to the intellectual property underpinning the Oxford gene therapy programme.

Choroideremia is caused by a mutation in a gene that makes a protein called REP1. It affects an estimated one in 50,000 people and causes sufferers, who are mainly men, to lose their sight gradually as the cells in the retina degenerate.-Reuters